Recent developments in fluorescent and colorimetric chemosensors based on schiff bases for metallic cations detection: A review

Hugo Schiff (1864), was the first who synthesized Schiff bases by the condensation reaction of primary amines with carbonyl compounds (aldehyde or ketone). Schiff bases display several structural and electronic features that allow their application in different fields, ranging from medicinal to chemosensing. Schiff bases coordinate with various metal ions and form stable complexes. Due to their excellent coordination ability, Schiff bases are used as fluorescent turn-on/turn-off and colorimetric chemosensors for the detection of different metal cations including Ag⁺, Cu²⁺, Co²⁺, Mn²⁺, Cd²⁺, Hg²⁺, Ni²⁺, Zn²⁺, Pd²⁺, Fe³⁺, and Al³⁺ in different samples. This review article covers a wide range of Schiff bases used in chemosensing applications for various metal ions (e.g., monovalent, divalent and trivalent cations) in different biological, agricultural and environmental media.